With the increased activity in deepwater exploration, the demand for reliable and intervention-less completion technology has greatly increased. Completion technology that reduces operational risk and project cycle time ultimately allows operators to economically exploit hydrocarbon reserves throughout the world. This paper will discuss the development and application of a new intelligent well system technology that is reliable and completely intervention-less.
One of the initial reasons for the development of intelligent well systems was to enhance project economics by reducing the reserve development cost. Intelligent well systems, which must have very high reliability1, accomplish this by allowing future proved reserves to be accessed during the initial completion phase, thus negating the need and expense for future rig intervention. The combination of reduced rig cost and accelerated production profiles greatly enhance total project economics.
Initial intelligent well completions focused on the ability to remotely control reservoir access from surface facilities. Again, the idea was to access multiple reservoirs with the need of exhausting reserves without expensive workover operations2. As this technique began to evolve, additional aspects of the completion process began to emerge which were not addressed utilizing conventional completion techniques.
Based on these issues, objectives were defined for a next generation intelligent well completion system which would integrate all aspects of the completion from sand control to placing the well on production.
Primary objectives were:
Maintain fluid loss and well control at all times prior to the initiation of production
Reduces fluid loss and formation damage
Greatly lowers the risk of a well control situation during time period of running production (several days)
No mechanical post completion intervention required
Lower trouble profile for well operations
Reduced time to completion
Utilize simple reliable technologies
Independent hydraulic flow control mechanisms
Simple pressure actuated fluid loss devices
Redundant capabilities for backup operations
Maximize production potential by maintaining optimum flow areas
Maximize inflow areas by maintaining large bore
Minimize formation damage by limiting formation exposure
These objectives were systematically applied to completion operations beginning with the lower zone sand control up through placing the well on production. The resulting developments form an integrated system that allows the entire completion to meet the outlined objectives.
In the past, lower zone completions utilized mechanical sleeves to gravel pack, isolate and then produce the reservoir. These sleeves were normally run concentrically inside the lower zone screen assembly and mechanically manipulated after the gravel pack was complete. It was necessary to utilize slickline or coiled tubing to reopen the sleeves for production. This system did, however meet all the necessary criteria for fluid loss and zone control. It was not, however totally intervention-less.
The intervention-less solution to this problem was a derivative of systems originally developed for the upper zone. These systems included a pressure actuated fluid loss control valve (PAFCV) along with a spin-off of this device, an annular flow valve (AFV